I have a 1986 Jaguar XJS. Just put a new radiator in and am getting it up to state code. Took it to the bank, home, and them post office. Started after 3 rotations max all day. Today, I went to get the reinspection done now that I have fixed the driverside window working. Wouldn't start. She's getting spark, I hear the pump prime the system, I've replaced the main relay to the ECU in the trunk, I've fiddled with the ignition switch and all seem in order.

What I did notice today was a high pitch whine coming from under the hood. (bonnet for our British friends) sounded like something building up electricity. When the key was turned off the noise vanished. I tried to replicate the sound and could only get it ever 2 or 3 key turns.

 

How does the starter sound when turning over?

 

Sounds pretty strong to me. It's the same one that was in it when I bought it 3 years ago. I've not heard very many XJS start ups since I'm the only persons I know with one.

 

It otherwise sounds like it is turning over at a fairly normal rate though, just not firing?
You pulled a plug to confirm spark? You need to confirm fuel before going further, listen for the injectors firing and consider checking for fuel at the rails. Without a helper, you can't really listen for the injectors though.

 

With the key 'on' operate the throttle turntable by hand. You should hear the injectors click....and by the way they'll actually give a squirt of fuel. This greatly aids in starting if the cars has been sitting. This arrangement, perhaps unintentional, is unusual for F.I. systems but there you have it!

Anyhow, if the injectors click you know the circuit is at least fundamentally operational....although it doesn't prove it operating 100% correctly



Cheers
DD

 

So, checked the injectors, spark and fuel jumped off my mother's Chrysler (she was in my area, only luck today). Had finally gotten it to start so I let it Idol while I put tools away. Ran for 10 minutes and then promptly died. Got it started by opening the throttle and turning the key as it was trying to kick off but just wouldn't, it ran for another 2 minutes, died and now it won't start at all. When I checked the fuel lines coming off the rail it actually had a back up of fuel that shot out at me a bit.

 

Yeah FI lines have a good deal of pressure. Did it idle normally when you had it on? What kind of rpm? You are sure it actually has gas in it, regardless of what the gauge says?

 

I filled it up to full last Saturday and haven't driven it to much since. It idled about 6-700rpm which is what it has done since I've gotten it.

 

Update: Missed my reinspection again. She turned and turned nearly fired once but after that there was no joy. Smells like fuel now. Looking on top of the engine on the left bank is a ignition amplifier with a spark sending unit that seems to be in every car ever, could that be a problem?

 

I think what you're referring to is the AC Delco 4-pin type ignition module, part D1906. Yes, it could be a problem....and not too painful as guesses go.

Take a look at the wiring from the amp as well. ....with particular attention to the wire that has the braided strands that look like co-ax cable.

Cheers
DD

 

The ignition control module seems to have been the problem. I installed a new one a let her run for 15 minutes straight without a problem. Cranked it up 2 hours later and took a 30 minutes drive to my brother-in-law's birthday dinner without a hitch and then home without a hiccup. I'm still going to check all suggested but she's up and running for now and that's what counts. Thank you to everyone and I hope not to be posting a new problemishes in the near future.

 

Nice!